1. Field of the Invention
This invention relates to a system for testing digital circuits and, more particularly, relates to a system for high speed testing of both integrated logic and array circuits.
2. Description of the Prior Art
The testing of electrical characteristics of integrated circuits is of prime importance in the manufacture of electronic devices, especially for use in data processing equipment which requires extremely high reliability. Because of the large number of circuits in an integrated circuit chip, it is very desirable to test the chip or wafer during development, before releasing the chip design to manufacturing. However, the trends today in integrated circuits of increasing even more the number of circuits per chip and of merging logic and memory arrays on the same chip make testing of these chips a difficult and complex problem. As the number of circuits change, the pin count also changes and the tester must be sufficiently flexible to handle a variable pin count. Today, there exists slow speed DC testers which can handle variable pin counts, and high speed functional testers with limited and fixed pin counts. However, there is need for a combination tester (DC and functional) which will handle variable pin counts and operate in a mixed mode by testing both array and logic circuits.